This is a setting on the fax machine, it has nothing to do with the ATA or FreePBX. Generaly, the TEL/FAX setting means you need to manually pick up the handset and press the start button on the fax machine to start receiving the fax, at least that is the meaning on several brands, like panasonic or samsung. If you want automatic fax answering, look for the corresponding setting, like AUTO or FAX only.
Thank you very much. I was driving to the customer and configured his Fax machines. They where set to Manual. On my next PBX project i will take a look over his fax machines and configure them directly when i setup the pbx.
But i dont understand how the machines worked over the last years with manual mode before switching to VoIP…